.sup.99m Tc labelling isonitrile compounds have been proven to be myocardial perfusion agents. The synthesis of ether isonitrile ligands has been described by Bergstein et al in European Pat. 233368 issued Oct. 26, 1987. The most useful of ether isonitrile compound is 2-methoxyisobutylisonitrile, synthesis of which is described by Bergstein as follows: ##STR1##
In both of the above (A) and (B) synthetic routes, which include 4 and 5 steps respectively, the total yield is only 5.9-8.1%. Van Wyk et al. developed a method to synthesize both 2-methoxyisobutylisonitrile and 2-ethoxyisobutylisonitrile, which was published under the title "Synthesis and .sup.99m Tc Labelling of MMI(MIBI) and its Ethyl Analogue EMI", Appl. Radiat. Isot. 1991, 42:687 ##STR2##
The possible contamination of mercury on the product is a disadvantage of the above process. There is a question of whether or not mercury acetate reagent affects products in the second step. Accordingly, we have invented a new simple and efficient method to synthesize 2-alkoxyisobutylisonitrile compounds.